Advances in semiconductor processing and logic design have permitted an increase in the amount of logic that may be present on integrated circuit devices. As a result, computer system configurations have evolved from a single or multiple integrated circuits in a system to multiple hardware threads, multiple cores, multiple devices, and/or complete systems on individual integrated circuits. Additionally, as the density of integrated circuits has grown, power and thermal requirements for computing systems (from embedded systems to servers) have also escalated. Furthermore, software inefficiencies, and its requirements of hardware, have also caused an increase in computing device energy consumption. In fact, some studies indicate that computing devices consume a sizeable percentage of the entire electricity supply for a country, such as the United States of America. As a result, there is a vital need for energy efficiency and conservation associated with integrated circuits. These needs will increase as servers, desktop computers, notebooks, Ultrabooks™, tablets, mobile phones, processors, embedded systems, etc. become even more prevalent (from inclusion in the typical computer, automobiles, and televisions to biotechnology).
To enable long term life of modern processors, a thermal loadline specification methodology is used. This methodology calls for lower temperature operation at lower power levels, and higher temperature operation is allowed if the processor is dissipating higher power. This specification is typically realized as a curve of temperature with respect to power. By controlling a processor with this methodology, an average operating temperature of the device is reduced over lifetime. While this loadline specification methodology works favorably for a single die, it does not extend to multiple die processors, as different dies incorporated into a package have different temperature limits. In addition, the loadline specification does not extend as package power becomes the sum of powers of all devices in the package, and operating temperature of dies in the package is determined not only by the total power of the package, but also by how the power is distributed among the various dies.